1. Field of the Invention
The invention relates to a grate furnace with a grate having grate steps including grate elements lying next to one another, every second grate step in the longitudinal direction of the grate can be driven for carrying out stoking movements and the grate steps in each case lying therebetween are stationary, the drive devices for the movable grate steps being arranged under the grate.
2. Description of the Prior Art
Known grates of grate furnaces with alternately arranged fixed and movable grate steps had a continuous stepped beam under the grate, to which beam the grate steps to be moved were connected and which beam had a single drive. In this connection, it was possible to arrange the drive device for this beam outside the grate, so that this drive device was not impaired by hot materials falling through the grate.
With the endeavor to influence the combustion process on the grate in a still better way, the approach changed to providing separate drive devices in each case for individual or grouped-together movable grate steps. In a first variant, these devices were then located at the side next to the actual grate module, which complicated or made more difficult a multiple-path arrangement of these grate modules next to one another and required drive linkages which were difficult to seal. When, according to a second variant, the drive devices were located under the grate, there were always disadvantageous consequences when hot materials came through the grate. If hot and perhaps sticky materials in liquid form drip onto the piston rods of cylinder/piston units and solidify there, this then leads very rapidly to the piston rod seal being damaged and thus to the failure of this drive device. The consequence of the failure of a drive device is the relatively long-term shutdown of the grate furnace.